1. Field of the Invention
The present invention relates to an apparatus and method for manufacturing a crash pad. More particularly, the present invention relates to an apparatus and method for manufacturing a crash pad, by which productivity can be improved and expenses and costs can be cut down through reduction in the number of molds and the number of processes, and deletion of manual operations, the problem of excessive loss of foam liquid due to leakage can be solved, and the degree of freedom of design of the crash pad can be improved.
2. Description of Related Art
Generally, a crash pad as an interior material is installed in the front indoor portion, such as a driver's seat or the seat next to the driver, to protect a passenger in the case of any car accident.
The crash pad is manufactured to have elastic cushion capability and a property of absorbing a shock of some level, while having an elegant-looking surface state, by using a foam material.
Typically, a crash pad for a vehicle includes a skin for providing an elegant-looking surface state and a core serving as a frame of the crash pad inside the skin. Between the skin and the core is interposed a foam layer, such as a polypropylene (PP) foam, polyurethane (PU) foam, etc., to provide a cushion function and a shock absorbing function.
FIGS. 1A through 1D are diagrams showing a conventional process of manufacturing a crash pad, in which a base 1 is formed by high-polymer injection molding, a skin 2 is formed by vacuum molding, and a foam layer 3 is formed by foam molding. The process will be described with reference to FIGS. 1A through 1D.
First, the base 1 is formed by low-pressure injecting a high-polymer resin material into an injection mold composed of an upper mold 12 and a lower mold 11 as in FIG. 1A. The skin 2 is inserted and pre-heated in a vacuum mold 13 of a male type and then is vacuum-adsorbed for vacuum molding as in FIG. 1B.
After a foam liquid 3a is injected onto the base 1 of the lower mold 11, a foam upper mold 14 to which the skin 2 is attached is closed, such that the skin 2 attached to the upper mold 14 is pressed and bonded onto the foam liquid 3a of the lower mold 11.
Thereafter, unnecessary edge portions (foam liquid leakage portions, etc.) of the molded skin 2 and foam layer 3 are cut together to be removed (trimming), and the edge portions of the skin 2 are urged to enclose the foam layer 3 and are adhered and fixed to the base 1 by means of an adhesive.
FIG. 2 is a cross-sectional view showing a state in which the edge portions of the skin 2 are bonded and fixed to the base 1 in the conventional process. FIG. 2 shows an enclosing process (enclosing the edge portions of the skin 2) conducted in undercut portions of edge portions of a product.
In the enclosing process, in a state where unnecessary portions formed by leakage of the foam liquid are removed, an adhesive is applied to end portions of the base 1 and the foam layer 3, and the edge portions of the skin 2 are manually adhered and fixed to the end portion of the base 1 in such a way to enclose the end portion of the foam layer 3.
However, the foregoing conventional manufacturing method has some problems as described below.
First, the base, the skin, and the foam layer have to be formed in separate molds, such that a total of three molds (upper mold and lower mold for base injection, a vacuum mold, a foam upper mold) are required, and a total of four processes including base injection, skin forming, foam molding, and cutting (and enclosing) are required, such that the number of processes is excessive.
In addition, enclosing of the skin is manually performed in the undercut portion of the edge portions of the product, and an additional process of applying an adhesive for enclosing is required.
As a result, an investment cost such as a mold cost increases, and due to a long time of the whole processing, productivity is degraded, also increasing the cost.
Moreover, the foam upper mold and lower mold are structured such that cavity edge portions are open even in their closed state.
Consequently, the foam liquid may leak through the cavity edge portions, and because the foam liquid has to be injected into a cavity space (foam cavity) whose one side is open, the foam liquid injection temperature has to be precisely maintained and controlled within a specified temperature range.
In the structure where the foam liquid may leak and the structure where the foam space is opened, the minimum thickness of the foam layer has to be designed to be a uniform thickness of a predetermined thickness (e.g., 5 mm) or more due to the early hardening of the foam liquid, which degrades the degree of freedom of design of the crash pad (the problem of open foam).
Furthermore, due to the structure where the foam liquid may leak, excessive loss of the foam liquid may occur, also increasing the cost.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.